生物挥发性有机化合物(BVOCs),它们是由植物生产和排放的,在大气中具有显著的化学反应性并影响气候变化。青海省,高原的重要组成部分,拥有丰富的植被资源,主要是草原和森林,然而,BVOCs的排放及其对空气质量的影响仍未得到充分研究。在这项研究中,采用闭环剥离动态顶空采样方法结合GC-MS对青海省7种主要植被类型BVOCs的排放速率和组成进行了采样和分析,利用G95模型估算了青海省2021年BVOCs排放总量。同时,还分析了各种植被类型的排放特征。结果表明,不同植被类型BVOCs的排放速率和组成存在显著差异,单萜是针叶林中的主要排放成分,占BVOCs总排放量的70%以上,虽然异戊二烯是高寒草甸的主要成分,占84.96%。三种典型植被类型的排放,云杉,高山草甸和高山草原,每天都被监控,揭示出明显的昼夜和清晰的单峰模式。研究还发现,青海省植被源BVOCs年平均排放量为1550.63Ggyr-1,其中异戊二烯的排放量比例最高,占56.94%。草原是青海省最大的BVOCs排放源,年平均排放量为1438.52Ggyr-1。此外,青海省BVOCs排放呈现较强的季节和日变化规律,夏季排放量最高,7月的高峰。这些发现提供了青藏高原植被源BVOCs排放的特征,这将有助于更好地了解它们对大气化学和气候变化的影响。
Biogenic volatile organic compounds (BVOCs), which are produced and emitted by plants, have significant chemical reactivity in the atmosphere and impacting climate change. Qinghai Province, a vital component of the plateau, has abundant vegetation resources, primarily grasslands and forests, yet BVOCs emissions and their impact on air quality remain understudied. In this study, the emissions rates and compositions of BVOCs from seven dominant vegetation types in Qinghai Province were sampled and analyzed using a closed-loop stripping dynamic headspace sampling approach combined with GC-MS, and the total emissions of BVOCs in Qinghai province in 2021 were estimated by using G95 model. At the same time, the emission characteristics of various vegetation types were also analyzed. The results showed that the emissions rates and compositions of BVOCs differed significantly among vegetation types, with monoterpenes being the dominant emission composition in coniferous forests, which accounted for >70 % of the total BVOCs emissions, while
isoprene being the main composition in alpine meadow, accounting for 84.96 %. The emissions of three typical vegetation types, Picea asperata, alpine meadow and alpine steppe, were monitored daily, revealing significant diurnal and clear unimodal patterns. The study also found that the annual average BVOCs emissions from vegetation sources in Qinghai Province were estimated to be 1550.63 Gg yr-1, with
isoprene contributing the highest proportion of emissions, accounting for 56.94 %. Grassland was the largest BVOCs emission source in Qinghai Province, with an annual average emission of 1438.52 Gg yr-1. Additionally, BVOCs emissions in Qinghai Province showed strong seasonal and daily variation patterns, with the highest emissions occurring in summer, with the peak in July. These findings provide the characteristics of BVOCs emissions from vegetation sources in the Tibetan Plateau, which will contribute to a better understanding of their impact on atmospheric chemistry and climate change.